The invention relates to an apparatus and a method for producing round brushes, which have bristles twisted in between two portions of wire of a folded wire, the apparatus having a bristle feeding device and a rotary gripper for twisting two portions of wire with bristles located between them.
Such apparatuses along with associated production methods are known in various forms. For example, EP 1 917 886 B1 discloses a method and an apparatus in which bristles are fed between two portions of wire of a previously folded wire, the portions of wire are twisted at a first winding station to the extent that the bristles are held between the portions of wire and the brush prefabricated in this way is fully twisted, to a desired degree of winding, at a second winding station. However, this is very complex due to the large number of working stations. Moreover, such an apparatus is only suitable for relatively small brushes such as mascara brushes, since in the case of larger brushes with longer bristles the covering material may be flung away by the centrifugal forces acting during the twisting. In order to minimize this effect, it has previously been the practice in the production of larger brushes for the covering material to be held by an operator until the covering material is clamped between the portions of wire. This requires considerable expertise and experience on the part of the operator and presents a hazard for the operator, since he must have his hands in the danger area of the apparatus during the twisting. Moreover, this production method does not represent a safe process and is only possible for brush dimensions that can be handled by an operator.
Although, for example, DE 10 2005 045 827 A1 or U.S. Pat. No. 3,791,421 A disclose apparatuses with which bristle material can be twisted automatically in between two portions of wire, these apparatuses require feeding of two separate portions of wire. As a result, both ends of the brushes must be worked after the twisting in of the covering material and a certain distance is necessary between the head end of the brush and the beginning of the bristle covering.